All study participants will also complete 3 tests, called sensory tests, that are designed to help researchers learn how sensitive patient is to things such as cold and touch. These tests involve feeling cold objects, feeling bumps on a rectangular board, and putting pegs into holes on a board. Patient will also be asked to mark on computerized drawings the areas where they experience any pain, numbness, and/or cold sensitivity. A study staff member will explain how to take the tests and use the computerized drawings in more detail at the time these tests are performed.